Greening Your Roof

Trying to green or sustain any building component these days is like trying to watch a moving target, and roofs are a prime example. In this column, I’ll take a look at where we are (at least at this particular moment) on the path toward more environmentally friendly alternatives to design and roofing materials. The first design consideration that relates to the greening of roofs is water runoff. We want to keep as much water on the site as possible to improve water levels in the aquifer, but we also need to keep water on site in such a way as to prevent damage to the residential structure itself. I have troubleshot many roofs whose design permitted several hundred ft2 of roof to carry rainwater or snow melt to only 2–4 ft of gutter.This often creates serious ice backup problems in cold climates and rain backup and/or spillage in most climates when 1 or more inches of rain come down in just a brief time. Some architects and builders have designed homes with no gutter system, but with an effective drainage system around the foundation, ...